Re: GConf - defaults.

[Owen Taylor <otaylor redhat com>]

Dietmar Maurer <dietmar ximian com> writes:

> Owen Taylor wrote:
> 
> > Dietmar Maurer <dietmar ximian com> writes:
> >
> > > Owen Taylor wrote:
> > >
> > > > Dietmar Maurer <dietmar ximian com> writes:
> > > >
> > > > Well, the problem with writing:
> > > >
> > > >  GError *error = NULL;
> > > >
> > > >  level = gconf_client_get_int (c, "user_level", &error);
> > > >  if (error)
> > > >    {
> > > >      level = DEFAULT_LEVEL;
> > > >      g_error_free (error);
> > > >    }
> > > >
> > > > is not just the problem with writing this all over the place, but it
> > > > is also that these fall back defaults don't get used at all normally,
> > > > so they'll rot, and may not work at all.
> > >
> > > Why don't we simply use:
> > >
> > > level = bonobo_pbclient_get_int_with_default (db, "user_level", 0, NULL);
> >
> > To reiterate:
> >
> >  * Hardcoding defaults into multiple places in the code is _evil_,
> >    because they _will_ get out of sync.
> 
> As you already mentioned, that default will only be used if everything else
> does not work. It is not the suggested method to hardcode defaults. It is
> totally pointless it that value is out of sync, since it will not be used
> normally. It is only a way to make the application more robust. Anyway, if
> gconf can really provide default values under all circumstances there is no
> problem at all.

Well, I can't claim that providing a value that isn't used makes things
work worse. But

  Why should people have to provide it at all if it is never used at all?
*- If it ever does get used, it will quite likely be wrong, since it isn't
   tested or kept in sync with the real defaults.
 
> Another reason for providing those functions is because it was already there
> in gnome_config_*, and it is also very useable to read PropertyBags associated
> with Controls.

I didn't suggest that you remove that function :-), though I would suggest
that people shouldn't be using it for config settings (when migrating from
gnome-config, you should be moving your defaults into scheme files).
And I would wonder - if you try to get a value from a propertybag that
doesn't have the property or has the wrong type for that property,
isn't that a bug in the program that should reported with g_warning(),
so it can be fixed?

Regards,
                                        Owen